ISSN 0439-755X
CN 11-1911/B

›› 2009, Vol. 41 ›› Issue (11): 1054-1062.

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Maintenance and Manipulation in Working Memory: Differential Ventral and Dorsal Frontal Cortex fMRI Activity

Sara Pudas, Jonas Persson, L-G Nilsson & Lars Nyberg   

  1. (1 Department of Psychology, Stockholm University, 106 91 Stockholm, Sweden)
    (2 Departments of Integrative Medical Biology (Physiology) and Radiation Sciences (Diagnostic Radiology), Umeå University, 90187, Umeå, Sweden)
    (3Umeå Center for Functional Brain Imaging (UFBI); 4Stockholm Brain Institute)
  • Received:2009-09-11 Revised:1900-01-01 Published:2009-11-30 Online:2009-11-30
  • Contact: Sara Pudas

Abstract: A verbal working memory protocol was designed and evaluated on a group of healthy younger adults in preparation for a large-scale functional magnetic resonance (fMRI) study on aging and memory. Letters were presented in two critical conditions: (i) maintenance, in which letters were to be memorized and kept in mind over a four second interval, and (ii) manipulation, in which letters were shifted forward in alphabetical order, and the new order was kept in mind. Analyses of fMRI data showed that the protocol elicited reliable activation in the frontal cortex, with manipulation producing more extensive activation patterns, both in whole-brain analyses and in predefined regions of interest (ROIs). There was also a distinction between dorsal and ventral lateral prefrontal regions, such that manipulation elicited more dorsolateral prefrontal activation. The protocol also elicited activation in various subcortical areas, previously associated with working-memory tasks. It was concluded that this working memory protocol is appropriate for investigating age-related changes in frontal-cortex functioning.

Key words: Frontal cortex, fMRI, working memory, maintenance, manipulation